116 OUR BIRD ALLIES. 
Now and again, too, the rook, like the raven and 
the crow, is apt to visit the coverts and appear in the 
guise of an amateur poacher, making off with a young 
bird or two, or perchance a nest of eggs; and it has 
been noticed while “quartering” the ground, just as 
has already been described of the hooded crow. 
But all such illicit seizures, whether of game, fruit, or 
corn, form but a very small set-off to the immense 
benefit conferred by the rook upon agriculture by its 
incessant slaughter of injurious insects, and notably 
of such giants of mischief as the cockchafer grub, 
the wireworm, and the grub of the daddy-longlegs 
(Zipula). All three of these creatures, living beneath 
the soil, are not only inaccessible to ordinary means 
of destruction, but attack the different crops in their 
most vital parts, devouring the roots, and so render- 
ing inevitable the speedy death of the infested plants. 
And very few roots escape their ravages. Corn 
suffers terribly from their jaws, and all root-crops are 
injured greatly by them, while, to descend to produce 
of less importance, the Rev. C. A. Johns states that 
he has known a large portion of a bed of garden 
lettuces destroyed by a single cockchafer larva, 
which he followed up from root to root, and finally 
captured as it was beginning upon a previously un- 
touched plant. And every farmer and every gardener 
knows the extent of the mischief wrought by 
wireworms. I have found a large mass of tubers of 
the Jerusalem artichoke so eaten away by them that 
barely one-half of the substance remained. And, as 
the grub of the cockchafer lives for three and the 
